1. Field of the Invention
The present invention relates to a novel metal complex and an organic light-emitting device including the same.
2. Description of the Related Art
There have been vigorously conducted developments of light-emitting materials with a view to provide an organic light-emitting device (LED) which emits light stably with high efficiency. In particular, developments of phosphorescent light-emitting materials have strenuously been conducted because phosphorescent light-emitting devices utilizing phosphorescence can emit light with high efficiency. There have been conducted developments of cyclometalated iridium complexes using a cyclometalated bidentate ligand (C—N) of Ir(C—N)3 and (C—N)2IrAcac types and cyclometalated platinum complexes (see, “Highly Phosphorescent Bis-Cyclometalated Iridium Complexes: Synthesis, Photophysical Characterization, and Use in Organic Light Emitting Diodes”, Lamansky, S.; Djurovich, P.; Murphy, D.; Abdel-Razzaq, F.; Lee, H.-E.; Adachi, C.; Burrows, P. E.; Forrest, S. R.; Thompson, M. E., J. Am. Chem. Soc.; 2001; 123(18); 4304-4312, and “Synthesis and Characterization of Phosphorescent Cyclometalated Platinum Complexes”, Brooks, J.; Babayan, Y.; Lamansky, S.; Djurovich, P, I.; Tsyba, I.; Bau, R.; Thompson, M. E., Inorg. Chem.; 2002; 41(12); 3055-3066).
Recently, there have been reported an iridium complex and a platinum complex using a cyclometalated terdentate ligand (see, “Synthesis and Luminescence of a Charge-Neutral, Cyclometalated Iridium (III) Complex Containing N^C^N- and C^N^C-Coordinating Terdentate Ligands”, Wilkinson, A. J.; Goeta, A. E.; Foster, C. E.; Williams, J. A. G., Inorg. Chem.; 2004; 43(21); 6513-6515, and “An Alternative Route to Highly Luminescent Platinum (II) Complexes: Cyclometalation with N^C^N-Coordinating Dipyridylbenzene Ligands”, J. A. Gareth Williams, Andrew Beeby, E. Stephen Davies, Julia A. Weinstein, and Claire Wilson, Inorg. Chem.; 2003; 42(26) pp 8609-8611). The iridium complex disclosed in “Synthesis and Luminescence of a Charge-Neutral, Cyclometalated Iridium (III) Complex Containing N^C^N- and C^N^C-Coordinating Terdentate Ligands” above has low stability and is particularly unsuitable as a light-emitting material because the iridium complex is decomposed in an excited state upon PL measurement for observing light emission when irradiated with light. Meanwhile, the platinum complex disclosed in “An Alternative Route to Highly Luminescent Platinum (II) Complexes: Cyclometalation with N^C^N-Coordinating Dipyridylbenzene Ligands” above has relatively high stability and a high emission quantum yield and is therefore suitable as a light-emitting material. However, according to the report, synthesis of the complex requires a step of refluxing for 3 days, so that there has been a problem in manufacturing that the step of synthesizing a complex takes an extremely long period of time. In addition, there has been a technical problem that the degree of freedom of selection of emission colors of the phosphorescent materials is low, so that there has not been particularly obtained a phosphorescent material of blue color emission with good performance.